The present invention relates to oil field drilling operations and the like, and more particularly to an apparatus for guiding and running wireline through a drilling platform and into a well bore.
Well bores of oil wells and the like are typically drilled and operated from a drilling platform, such as an offshore drilling rig. FIG. 1 shows an upper surface of a drilling platform 130. A rotary table 120 is positioned on the surface of the drilling platform 130. The rotary table 120 has a centrally disposed opening. A removable insert bowl 10 is inserted in the opening of the rotary table 120. The insert bowl 10 consists of two substantially identical half pieces 10A and 10B. Insert bowls 10 are manufactured to standard specifications and distributed by numerous companies, including Varco B. J., Dencon, Access Oil Tools, and Texas International Oil Tools. The insert bowl 10 functions as a bushing to protect components that pass through the rotary table 120 during drilling and production operations. One such component is the drill string 110, which passes through the rotary table 120 and into a well bore (not shown) located under the drilling platform 130. The insert bowl 10 also holds slips (not shown), which hold the pipe of the drill string 110.
In drilling operations, logging tools and the like arc often run into the well bore for various purposes, such as to evaluate the progress of the well bore and to identify characteristics of the subterranean strata surrounding the well bore. Logging tools arc run into the well either on the end of the drill string 110, or without the drill string being present. Logging tools and the like are operated via the wireline 100 shown in FIG. 1. The wireline 100 conducts electric signals between the logging tool and the surface of the well, and also serves as a cable for supporting the logging tool and retrieving the tool from the well bore.
In the apparatus and methods of the prior art, the insert bowl 10 is not equipped with the groove 20 and rotation means 50 shown in FIG. 1, but instead consists of two half pieces 10B. In the prior art wireline methods, the wireline 100 typically rides directly along the interior surface of the insert bowl 10B. The interior surface 12 of the insert bowl 10B acts as a bushing to protect the wireline 100. However, tension in the wireline 100 is typically in the order of 300-400 pounds, and rubbing of the wireline 100 against the insert bowl 10B under such tensions is sufficient to damage both the wireline and the interior surface 12 of the bowl 10B. Tension in the wireline can reach 1000-2000 pounds under certain conditions, such as on floating oil rigs during rough seas. Additionally, rotating and/or sliding the drill string 110 during drilling operations may damage or cut the wireline 110. Replacement of broken wireline and damaged insert bowls 10 is expensive. Additionally, retrieving logging tools and broken wireline from the well bore consumes time and labor that could otherwise be devoted to setting drill string. Further, a snapped wireline 100 can cause serious injury to workers on the drilling platform 130.
The present invention provides an apparatus and methods for overcoming the foregoing problems and shortcomings of the prior art.
It is an object of the invention to provide an improved apparatus and methods for guiding and running a wireline into a well bore during wireline and drilling operations.
It is another object of the invention to provide an apparatus and methods for preventing damage to wireline when setting drill pipe slips.
It is another object of the invention to provide an apparatus and methods for avoiding damage to insert bowls.
It is another object of the invention to improve the efficiency of wireline and drilling operations by preventing broken wirelines, thereby reducing downtime caused by retrieval of broken cable and downhole tools.
It is yet another object of the invention to provide safer drilling conditions by preventing broken wirelines.
These and other objects and advantages of the invention shall become apparent from the following general and preferred description of the invention.
Accordingly, an apparatus for guiding wireline into a well bore is provided comprising an insert bowl, the insert bowl having a substantially vertical groove formed in an interior surface thereof. The groove preferably extends substantially from an upper end to a lower end of the insert bowl. A rotation means is preferably provided on the insert bowl, the rotation means configured and positioned to rotate against a wireline and maintain the wireline substantially in the groove when the insert bowl is positioned in a rotary table of a drilling platform, to thereby prevent damage to the wireline during wireline and drilling operations. The rotation means preferably comprises a support member and a wheel rotatably disposed in the support member, the support member being attached to a top of the insert bowl above the groove. The wheel is preferably configured as a sheave having a concave rim. The support member further preferably comprises a first block member positioned substantially along one side of the groove, a second block member positioned substantially along an opposite side of the groove, and an axle shaft passing between the first and second block members, the wheel being rotatably disposed on the axle shaft. A race is preferably disposed between the axle shaft and the wheel.
In a preferred embodiment, the rotation means may be readily dismantled after use for inspection and maintenance. In one such embodiment, the first block member has a hole therethrough and the second block member has a bore on an inner side thereof. The axle shaft passes through the hole of the first block member, and a first end of the axle shaft is disposed in the bore of the second block member. A keeper means is removably disposed on an outer side of the first block member for retaining the axle shaft in the bore and the hole during wireline and drilling operations. The keeper means preferably comprises a keeper block and at least a pair of bolts removably securing the keeper block to the outer side of the first block member. The apparatus is further preferably provided with a grease zert passing through an outer side of the second block member and communicating with the bore to thereby permit application of grease to the apparatus during wireline and drilling operations.
Methods of constructing and using the aforementioned apparatus are also described.